1. Field of the Invention
This invention relates to the construction of article guides for article handling systems, particularly the longitudinally extending drum partitions of linkless, drum type ammunition storage systems.
2. Prior Art
Linkless, drum type ammunition storage systems are well known, and are shown, for example, in U.S. Pat. No. 3,696,704 issued to L. F. Backus et al on Oct. 12, 1972, and the many other patents and publications cited therein, herein incorporated by reference. Conventionally, such systems comprise a central helix or auger rotating about a central, longitudinal axis within an outer drum having a plurality of centripetally directed, longitudinally extending guides or partitions disposed in an annular row about the central axis. Rounds of ammunition are stored in longitudinally extending columns with their bases respectively interlocked between adjacent partitions, and their tips respectively disposed between adjacent turns of the helix. As the helix rotates, it advances the rounds longitudinally. In a single ended system, only rounds are stored. In a double ended or closed loop system, fired cases are also returned and stored.
Generally, the center of gravity of an unfired round is well within the transverse area of the helix, and the round remains perpendicular to the longitudinal axis of the drum as the helix engages it between its center of gravity and its extractor disk and pushes it along between the drum partitions. In contradistinction, the center of gravity of a fired case is entirely outside the transverse area of the helix. The helix engages the case at the same point as with an unfired round, which point is not between its empty center of gravity and its extractor disk. When unloading the drum of fired, empty cases, the longitudinal movement of the empty cases leaves the last layer of empty cases unsupported by succeeding cases as the rear of the drum becomes progressively void of empty cases. The non-intermediate load applied by the helix causes this last layer to tilt within the clearance of adjacent turns of the helix. If there is a high frictional force between the extractor disk of the fired case and the drum partitions, the tilt tends to wedge the extractor disk between the drum partitions until it deflects the adjacent layer of the helix enough to permit enough tilt to cause a jam of the extractor disk between the drum partitions.
Accordingly, it is an object of this invention to provide a system which minimizes the frictional force developed between the extractor disk of a case and the drum partitions.
A feature of this invention is the provision of a system having drum partitions which ensure a rotation of the case about its own longitudinal axis within the drum partitions as the case is advanced parallel to the drum longitudinal axis along the drum partitions by the helix.